Monitoring water quality changes and ornamental fish behaviour during commercial transport

Abstract

Live transport of fishes is recognised as a major source of stress leading to poor welfare and mortality within the ornamental fish industry. While previous studies have aimed to simulate the stressors experienced by fishes during transport in the laboratory, there is little documented evidence of the actual conditions experienced by fishes under commercial conditions. The aim of this study was to monitor water quality and fish health (physiology and behaviour) through a commercial supply chain for three popular freshwater ornamentals (neon tetra, oranda, variatus platy). Water samples were collected at nine stages of the supply chain beginning at arrival of the fishes at a UK wholesaler from Singapore through their recovery at the wholesaler, to subsequent shipment to and recovery at retail stores. Water chemistry was recorded at various points in the transport chain and the water tested for common fish pathogens. Fish health parameters measured included mortality, injuries, waterborne cortisol and behavioural changes. Most water parameters were found to change significantly through the transport chain, including pH, carbonate hardness (KH), chloride (Cl−), nitrate (NO3−), sodium (Na+), magnesium (Mg2+), potassium (K+) and calcium (Ca2+). Pathogens were detected in the water at each stage of transport, but no disease outbreaks were observed. Mortality was low and was not affected by transport stage. Behaviour was found to change the most between different stages of transport. Neon tetras and orandas showed some behavioural changes during transport but the behaviour of variatus platys was more affected by transport stage. The findings of this study highlight the changes in water quality experienced by fishes during commercial transport that are often over-looked in simulated studies and confirm the need for species-specific indicators of welfare during commercial transport.